1. Field of the Invention
This invention relates to soil moisture sensing devices and more particularly to a novel automatic sensing device for providing water to the soil when needed for continued life and growth of plants, flowers or the like in response to the moisture content of the planting medium.
2. Brief Description of the Prior Art
In the past, it has been a well known practice to provide automatic watering devices, such as sprinklers, in order to supply plants with a proper amount of moisture so that the plants or natural growth will flourish. By providing a plant with too little or too much water, its growth progresses or life span will be impeded. Since the proper amount of moisture varies not only among different types of growth, but with the particular environment in which the plant is growing, it is a time consuming process to manually supply the necessary water. Automatic devices for providing the necessary water to the plant life are highly desirable and time saving devices.
However, the variability and unpredictability of the amount of water needed by a specific plant is difficult to forecast. Water should be supplied to the plant in response to the plant's need for the water and not, as is characteristic of prior art devices and practices, in response to an arbitrary standard such as time. Time responsive watering devices have been generally found unsatisfactory since a plant's need for water is not solely a function of time, but varies with conditions of the planting medium, the atmospheric temperature, humidity, etcetera.
For example, a conventional system employs a timer controller which operates a solenoid valve incorporated into a water supply system so that when the time as arbitrarily set by the user arrives, power is supplied via the solenoid to the water supply valve so that water is then supplied to a system of sprinklers or other irrigation devices. However, water may be supplied even though the ground or plant medium is saturated such as subsequent to a heavy rain or the like.
Therefore, a long standing need is present to incorporate into automatic water sprinkling systems, a detection device or apparatus which functions in conjunction with the timer to operate the water supply valve in response to the moisture content of the soil or plant medium.